Carburetor heat control



April 19, 1932.

D, FIRTH CARBURETOR HEAT CONTROL Filed Nov. 24, 1928 2 Sheets-Sheet 1 471/517 57.5 Dal (ii 7% D. FIRTH CARBURETOR HEAT CONTROL V 2 SheetsSheet 2 jai/z' 7%)7/7 Filed Nov. 24, 1928 A y M I M h 4 April 19, 1932.

Patented Apr. 19, 1932 UNITED STATES PATENT? OFFICE DAVID FIRTH, OF FLINT, MICHIGAN, ASSIGNOR TO MARVEL CARBURETER 60., OF FLIIIT, MICHIGAN, A CORPORATION OF ILLINOIS CARBURETOR HEAT CONTROL v Application filed November 24, 1928. Serial No. 321,529.

This invention relates to a carburetor heat control for internal combustion engines.

It is the principal object of this invention to provide an improved heat control adapted to compensate for varying conditions of temperature and operation. More specifically, the present invention relates to controlllng the heat supplied by an exhaust gas jacket associated with the carburetor and manifolding system of an engine. It has been recognized heretofore that the maximum heat supply should be available under closed throttle or idling conditions and that the heat supply should be reduced in proportion to the throttle opening in order that the maximum power may be developed with a relatively cool or unheated mixture supply under wide open throttle conditions. This result, in the case of an exhaust gas heated jacket, may be obtained by two methods First, the jacket may be connected in a by-pass passage around a control valve in the main exhaust pipe, in which case the valve is so linked to the carburetor throttle as to be opened in step therewith. The present invention has been shown as applied to this method of heat supply. The second method connects the carburetor jacket to an exhaust bleed connection from which the exhaust gases are discharged to the atmosphere. In this method a valve controlling the bleed connection is solinked to the throttle that it will operate oppositely to the carburetor throttle.

The present invention utilizes the prior structures heretofore mentioned and adds thereto a seasonal or temperature control adapted to delay the reduction of therheat supply, as the throttle is opened, as the operating temperatures decrease. In other words a full heat supply is maintained for a longer proportion of the opening movement of the throttle and the movements of the exhaust gas control valves and the throttle are shifted relative to each other and vary the supply of heat for a given throttle posit-ion.

It is accordingly an object of this invention to provide a heat control varied in response to the requirements of varying temperature conditions and independently of the required variation in heat supply for varying operating conditions. I accomplish this result by mechanism independent of but cooperating with the normal heat control.

It is also an object of this invention to provide a simple, easily manufactured and serviced seasonal temperature control that may be operated automatically by a thermostatic control.

Other and further important objects of this invention will be apparent from the disclosures in the specification and accompanying drawings.

The invention (in a preferred form) is illustrated on the drawings and hereinafter more fully described.

On the drawings:

Figure 1 is a fragmentary side elevation of an engine cylinder block showing the manifolding system incorporating the exhaust heat control of this invention.

Figure 2 is an enlarged fragmentary section on the line IIII of Figure 1 showing ghiadheat jacket surrounding the intake mani- Figure 3 is a section on the line IIIIII of Figure 2.

Figure 4 is a section of the main exhaust pipe control valve taken on theline IV-IV of Figure 1.

Figures 5, 6, and 7 are sections parallel, to Figure 1 through the valve of Figure 4, the three figures showing successive stages of the adjustments varying from cold to hot under idling conditions.

Figure 8 is a section showing the thermostatic control.

In Figure 1 a fragmentary portion of a cylinder block 10 is shown to illustrate the relative position of the exhaust manifold 11 and intake manifold 12 positioned thereabove in the illustrated embodiment. The intake manifold includes a vertical riser 13 to the bottom of which is secured a carburetorl l. The riser contains the usual carburetor butterfly throttle valve 15 operated by a throttle lever 16. The riser 13 is formed With a jacket space 17 connected to a branch opening 18 of the exhaust manifold 11 as best shown in Figure 3.

The exhaust manifold terminates in a flange to which is secured a valve body 21, the latter in turn receiving the end of the usual exhaust pipe 22. The jacket space 17, which may be called the exhaust jacket, has a lpwer outlet 23, connected by a flexible tube 24 to an inlet 25 on the exhaust valve body 21 below the Valve location. The branch open ing 18, exhaust jacket 17, outlet-23, tube 24 and inlet 25, thus form an exhaust bypass around the valve in the valve body 21, and this bypass is of unvariable area up to the inlet 25. A butterfly valve 26 is mounted in this inlet and may be termed the bypass valve as it is the sole direct control of the are-a of the exhaust bypass. The bypass is so tortuous, however, that this single valve would lack complete control as when wide open but little exhaust gas would flow through the jacket 17 because of the relatively less back pressure due to friction in the main exhaust manifold 11.

In order to cause a substantial amount of the exhaust gases to flow through the bypass, a butterfly valve 27 is provided in the valve body 21 above the bypass inlet 25 relative to the direction of flow of the gases. This valve ismounted in an enlarged cylindrical chamber 28 having its axis at right angles to the axis of the main exhaust passage 29 through the valve body. The butterfly valve 27 is operated by a lever 30 having a connection 31 to the throttle lever so that it is moved. in step therewith, being wide open when the throttle is open and being closed when the throttle is closed for idling, under which conditions a maximum heat flow is desired through the exhaust jacket 17. The amount of exhaust gases discharged by the-engine is of course a minimum under idling conditions so that the entire amount is bypassed through the 'acket, whereas under wide open throttle the ypass could not accommodate the full volume of exhaust gases and it would not be desirable to bypass the gases under such conditions because the excessive amount of heat supplied to the intake manifold would reduce the weight of a unit charge supplied to the enginecylinders and would thus decrease the maximum power output thereof. The arrangement so far described is adapted to vary the heat supply to the exhaust jacket 17 in inverse proportion to the throttle 0 ening. It is desirable to modify this rigi ,ratio for varying operating conditions which may be broadly classed as seasonal temperature variations as well as the different requirements for a cold and a warm engine which have the maximum variation in se- Verely cold weather and the minimum variadependently rotatable relative thereto. Thebarrel valve comprises a cylindrical shell with most of its surface cut away to leave diametrically opposite strips 33 forming the valve andadapted to cooperate with the edges of the butterfly valve 27 to modify the opening thereof. The valve 32 is operated by a lever 34 having an extension 35 linked at 36 to a lever 37 controlling the bypass valve 26; the linkage being so adjusted that for maximum heating conditions for coldweather the valve 26 is fully open when the barrel valve is in its extreme position, counter clock wise as shown in Figure 5. As the barrel valve is rotated clockwise the bypass valve 26 is moved to its closed position as shown in Figures 6 and 7.

The lever'34'may be operated by any conbe forgotten after starting as frequently happens with the customary manual carburetor choke control.

One method of accomplishing an automatic control of the barrel valve '32 is to mount a thermostatic device in the radiator 38 of the engine cooling system. I prefer to provide a chamber 40 in the bottom tank of the radiator and to mount abellows type of thermostat 41 in the chamber having a piston rod 42 engaging a pivoted lever 43 having a series of holes 44 to receive one end of a rod 45, the other end of which engages the lever 34. By

adjusting the rod 45 in different holes 44 the adjusting effect or temperature responslveness of the barrel valve 32 can be adjusted to suit the requirements of the different engines.

The 0pemtz0n.As the heat control variation in response to different throttle settings has been described hereinbefore it is believed to be unnecessary to' go into further details in regard thereto except as. will be brought out in the description of the thermostatic control.

A consideration of the linkage of Figures 1 and 8, wherein the thermostat is collapsed and the barrel valve set for a maximum supply of exhaust gases through the bypass jacket, as shown in Figure 5, will show that the barrel valve rotates clockwise as the thermostat expands from its collapsed position. The linkage connecting the throttle to the valve 27 causes the latter to rotate counter clockwise from the idling or shut off position all show the throttle controlled valve 27 as in the idling position and it should be borne in mind that the amount of exhaust gases produced by the engine under such conditions will find an ample outlet area through the bypass jacket and valve 26 in Figures 5 and 6 and between the edges of the valve 27 and the barrel valve strips 33 in Figure 7.

In Figure 5, which shows the condition for maximum heat supply under cold conditions at the thermostat, it will be evident that the valve 27 must be rotated through an angle equivalent to the are formed by the strips 33 of the barrel valve before the main exhaust passage is opened at all, thus maintaining a full flow of exhaust gases through the bypass passages during a portion of the initial opening movement of the throttle.

Figure 6 illustrates the adjustment of the barrel valve for temperate or mild conditions and a consideration of the counter clockwise movement of the valve 27 will show that while full heat is still supplied through the bypass for idling, the valve 27 immediately begins to open the main exhaust passage when the throttle begins to open. At the same time the bypass valve 26 is partly closed thus reducing the flow of exhaust gases through the bypass as soon as the main exhaust valve 27 has opened at all.

Figure 8 illustrates the valve adjustments for extremely hot conditions where no heat is necessary even for idling. The further rotation of the barrel valve as shown has opened passages around the edges of this valve 27 and at the same time has closed the bypass valve 26 thus cutting off the bypass passage.

It will thus be seen that I have produced an improved exhaust jacket heat control that is simple in operation and adaptable to the varying operating conditions of an engine subject to extremes of load speed and temperatures.

I am aware that numerous details of construction may be varied through a wide range without departing from the principles of this invention, and I therefore do not, propose limiting the patent granted, otherwise than necessitated by the prior art.

I claim as my invention:

1. In combination, a carburetor having'a throttle and a heating jacket, means for conducting a heating fluid through said jacket, control means associated with said first mentioned means and interconnected with the throttle for causing heating fluid to flow therethrough in amounts inversely proportional to the throttle opening, and thermostatically operated means cooperating with said control means for controlling the amount of heating fluid flowing therepast.

2. In combination wlth the intake and exhaust manifolds of an internal combustion engine, a valve in said exhaust manifold, a

jacket associated with said intake manifold and having bypass connections to said exhaust manifold around the valve therein, control means for said valve whereby to vary the diversion of exhaust gases through said bypass connections and the jacket, and a second control valve enveloping said exhaust valve and movable relative thereto, said control valve having ports adapted to vary the time of opening of said exhaust valve.

3. In combination with the intake and exhaust manifolds of an internal combustion engine, a valve in said exhaust manifoldfa jacket associated with said intake manifold and having bypass connections tosaid exhaust manifold around the valve therein, control means for said valve whereby to vary the diversion of exhaust gases through said bypass connections and the jacket, a valve in said bypass connections, a control valve enveloping said exhaust valve and linked to the valve in the bypass connections whereby to vary the relative flow of exhaust gases through said bypass connections independently of the control means for said exhaust valve.

4. In combination with the intake and exhaust manifolds of an internal combustion engine, a valve in said exhaust manifold, a jacket associated with said intake manifold and having bypass'connections to said exhaust manifold around the valve therein, control means for said valve whereby to vary the diversion of exhaust gases through said bypass connections and the jacket, a valve 1m in said bypass connections, a control valve enveloping said exhaust valve and linked to, the valve in the bypass connections, and thermostatic means adapted to operate said control valve.

5. In combination with the exhaust and intake manifold of an engine, and an exhaust heated jacket for the intake manifold, controllable means for diverting varying proportions of exhaust gases from said exhaust manifold through said jacket, and thermostatically controlled means for varying the effective range of movement produced by said controllable means.

In testimony whereof I have hereunto subscribed my name at Flint, Genesee County, 

